Routing devices (i.e. Routers) are principally responsible for forwarding data, typically in the form of packets, between computer networks, enabling the interconnectivity of the disparate networks that form the Internet. Each device in a network is uniquely identified by one or more addresses indicating its location in the network.
Routers connect data links from different networks. A router reads address information in an incoming packet to determine its destination, and performs a next (network) “hop” information lookup to the destination using its routing table. In this way, packets may be forwarded from one router to another through the networks that constitute the Internet until it reaches its destination node. Additionally, in order to conserve address space in addressing or labeling schemes such as IPv4, IPv6, MPLS, and MAC, routers map multiple addresses into fewer or even one address, and readdress the outgoing packets so they appear to originate from the routers (MAC address summarization is not typical given the number of Organizationally Unique Identifier (OUI) codes involved in MAC addressing but is not impossible).
On routing and switching equipment deployed by network operators and other operators in need of high-bandwidth routing and switching capability, most routing tables reside on integrated hardware such as Application Specific Integrated Circuits (ASICs) or Field Programmable Gate Arrays (FGPAs) with or without external Content Addressable Memory, where the space available for a routing table on any individual router is fixed at a limited size. Because each network and network element such as servers, PCs, smartphones, tablets, and other network-capable devices must be uniquely identified by its own address, the number of network hops and network elements that can be stored in the routing table for any one router is restricted by the size of the space available on the integrated hardware device.
In view of the foregoing, it would be desirable to provide infrastructure to allow extension of the existing routing and switching architecture without hardware upgrades or service disruptions.